Automatic pump for deep wells

ABSTRACT

An automatic pump for deep wells comprises a long stroke reciprocating pump having its piston normally in its bottom position and an automatic control dependent upon the collection of a predetermined amount of liquid in the pump cylinder above the piston for actuating the piston to pump the liquid into a production line. The automatic control includes a hydraulic pump and a reservoir of hydraulic fluid which is actuated upon filling of the reciprocating pump chamber to supply hydraulic fluid to a closed chamber below the piston and force the piston upwardly to discharge liquid from the pump cylinder. The hydraulic pump is reversed automatically upon completion of the pumping stroke of the piston.

This invention relates to an improved down hole pump for oil wells andthe like and particularly to a deep well pump for oil field use which isautomatic in operation and pumps at a rate determined by the rate offlow of the liquid of the well in which it is installed.

The present invention is an improvement on the invention of my U.S. Pat.No. 3,225,697 issued Dec. 28, 1965.

The deep well pump disclosed in my above patent has provided a systemwhereby liquids are pumped from the well only after a predeterminedvolume of liquid has entered the pump cylinder from the formation inwhich the well is located. Thus power is used only when thepredetermined volume of liquid has been accumulated; this represents asubstantial saving of energy over that expended for continuous lowvolume production pump operation. It is an object of my presentinvention to provide an improved deep well pump of the type whichoperates only in response to a predetermined accumulation of liquid.

It is another object of my invention to provide a deep well pump of theautomatic type including an improved arrangement for reducing the costof the equipment and the energy expended thereby.

It is another object of my invention to provide an automatic deep wellpump which is actuated in response to the accumulation of apredetermined amount of liquid in the pump cylinder and including animproved operating mechanism for the pump.

It is another object of my invention to provide an automatic deep wellpump including an improved arrangement utilizing an electric motor inthe pump assembly for actuating the pump.

Briefly, in carrying out the objects of my invention in one embodimentthereof, I provide a long stroke reciprocating pump and a hydraulicreservoir and a driving assembly including a hydraulic pump and anelectric motor for driving the hydraulic pump; the hydraulic pumpdelivers fluid from the reservoir which is mounted in the assembly abovethe long stroke pump. The fluid is delivered to a closed chamber belowthe piston of the reciprocating pump; when energized, the electric motordrives the hydraulic pump to deliver hydraulic fluid to the closedchamber and drives the piston upwardly thereby delivering the liquidfrom the cylinder to a production line. Check valves at the dischargeend of the pump cylinder prevent reverse flow of the liquid. The upwardmovement of the reciprocating piston is limited by a switch whichreverses the hydraulic pump at a predetermined point, thus reversing thepiston and returning the hydraulic fluid to the reservoir. The upperportion of the reservoir may contain a quantity of nitrogen or otherneutral gas, which provides a surge chamber action, the return of thefluid compressing the gas to the extent necessary.

The features of novelty which characterize this invention are pointedout with particularity in the claims annexed to and forming a part ofthis Specification. The invention itself, however, both as to itsconstruction and manner of use, together with further objects andadvantages thereof, will best be understood upon reference to thefollowing description taken in connection with the accompanying drawingsin which:

FIG. 1 is a diagrammatic sectional elevation view of a cased well in areservoir formation having installed therein a deep well pump embodyingthe invention;

FIG. 2 is an enlarged somewhat diagrammatic sectional elevation view ofthe pump of FIG. 1;

FIG. 2a is a diagrammatic illustration of a modified arrangement of thepump control.

FIG. 3 is an enlarged sectional elevation view similar to FIG. 2illustrating a modification of the pump assembly;

FIG. 4 is an enlarged sectional elevation view similar to FIG. 3illustrating a further embodiment of the invention.

The deep well pump of this invention is constructed so that it may bemade with a long stroke, for example, fifty feet or more, and so thatthe pump is actuated only when the pump cylinder has been filled withliquid to a predetermined level; thus the pump is actuated to deliverliquid in accordance with the rate of the supply of the liquid and inunits of volume each equal to the cylinder capacity.

Referring now to the drawings, FIG. 1 illustrates a pump assembly 10which is positioned within a well casing 11.

The casing is perforated to provide a multiplicity of inlet openings 12adjacent a producing formation 13; the shot holes extend from theopenings 12 into the formation for delivering formation fluids to theinterior of the casing. The pump assembly includes a cylindrical housing14 which is rigidly secured to and supported from a production tubing 15by a reducing fitting 16. The tubing is suspended from a well headassembly 17. Fluids from the formation enter the casing and, on reachinga plurality of openings 18 in the housing 14, enter the housing wherethe liquid is accumulated and then pumped to the surface.

Power for driving the pump in the assembly is supplied throughthree-phase alternating current lines 20 from a conventional powersource through a control unit 21. In this embodiment, the lines 20 passthrough the production tubing to the pump assembly.

Both the pump assembly 10 and the tubing 15 have been shown with breaks,since both the assembly and the tubing are of much greater length thancan be illustrated in proportion in the drawing.

In this figure, the power lines 20 have been illustrated as lyingoutside the production tubing and pump assembly housing and pass intothe housing through suitable insulating seals. The lines 20 preferablyare tied to the production tubing.

The internal arrangement of the pump assembly is shown in FIG. 2; thehousing 14 is cylindrical and has been illustrated as comprising upper,middle and lower sections 22, 23 and 24, respectively, which arethreaded together by tapered threads in accordance with well knownpractice. The middle and lower sections are connected by a plate fitting25 which constitutes a partition between these sections and divides thehousing 14 into an upper chamber and a lower chamber. The lower chamber,which is entirely within the section 24, is the cylinder of the deepwell pump, and a free piston assembly 26 is installed for reciprocationin the cylinder 24; this assembly being biased by gravity to itslowermost position in the housing. The upper chamber, which is definedby the two sections 22 and 23 has therein a hydraulic pump 27, anelectric drive motor therefor, and a reservoir or tank 30, which isfilled with hydraulic fluid either completely or to a level such asindicated at 31. The reservoir above the liquid may be filled with aneutral gas such as nitrogen. The pump 27 is connected to receive liquidfrom the tank 30 through an inlet 32 and to deliver liquid through asupply line 33 to an expansible chamber 34 below the piston assembly 26,the bottom of the housing 14 being closed by an end plate 35. In itslowermost position, the pump assembly 26 rests on a spring seat 35,which determines the minimum volume of the expansible chamber 34.

During the operation of the pump assembly, as liquid flows through theopenings 18 into the chamber above the piston assembly, it fills thechamber until it reaches a level indicated by a dotted line at 36 whichis below the level of the openings 18. Gas also may enter the chamberand accumulates above the liquid. When the liquid reaches the level 36,a float 37 rises and actuates a switch 38, which is connected by leads38' to the pump motor control and when actuated operates to start themotor 28 and drive the hydraulic pump 27. The motor has been illustratedwith a break because the motor is of the deep well type and may be verylong as compared with its diameter. The operation of the hydraulic pumpproduces a flow of high pressure liquid into the chamber 34 and thepiston assembly is driven upwardly increasing the pressure in the pumpcylinder, actuating check valves 40 to close the openings 18, anddelivering fluids through check valves 41 in the partition 25, thefluids being delivered to the production tubing 15. The hydraulic pumpand reservoir assembly is suspended within the housing 14 on a pluralityof lugs or hangers, one of which is shown at 42 as bolted to an upwardlyextending lug 43 at the top end of the section 22. The fluids flowfreely upwardly through spaces between the hangers and lugs.

When the piston assembly reaches its top position, it engages anoperating element 44 of a limit switch 45; the switch is connected byleads 45' to the pump control and the operation of the switch effectscontrol of the hydraulic pump to reverse the flow of hydraulic fluid.The hydraulic fluid is thus withdrawn from the expansible chamber belowthe piston assembly 26 and returned to the reservoir 30. This reversalof flow may be accomplished by selecting a reversible pump which isreversed by reversing the electric motor or by providing reversingconnections in the hydraulic circuit at the pump, either type ofreversal being effected by operation of the limit switch 45 or anothermethod of reversing the hydraulic fluid flow, the piston will strike arigid stop 45' which may be an annular ring rigidly mounted on theinside wall of the section 24. This stopping of the piston will producean abrupt rise in the pressure of the hydraulic liquid below the piston,and in the hydraulic pump which will actuate the high pressure controlof the hydraulic pump 27 to relieve the excess pressure.

Upon reversal of the flow of hydraulic fluid, the piston assembly 26returns toward its bottom position by gravity assisted by the removal ofhydraulic liquid from below the piston, and upon engaging the actuator46 of a switch 47 stops the motor 28 until another full load of liquidaccumulates in the pump chamber.

As shown in FIG. 2, the piston assembly 26 comprises a main piston 48mounted for sliding movement in the cylinder 24. Leakage between the topand bottom sides of the piston 48 is prevented by suitable annulargaskets or rings 50 mounted in annular grooves about the piston. Thepiston assembly may be weighted by adding a plate or disc, asillustrated at 51 to facilitate its return to its lowermost position.The disc is illustrated as secured to the piston by bolts 51'.

During the operation of the pump assembly, the fluids entering the pumpchamber through the openings 18 may carry some sand or other sedimentinto the chamber and this foreign matter will tend to settle in thebottom of the chamber on top of the piston assembly 26. In order tominimize the collection of sediment in the pump chamber, a device foragitating the sediment and creating turbulance is provided. For thispurpose, the pump assembly 26 is constructed by forming the main pistonas an upwardly opening cup thereby providing an internal cylindricalchamber 52 in which a piston 53 is slidably mounted. The chamber 52includes a large diameter portion 54 and a reduced diameter portion 55;these cylinder portions are formed by a flanged cylindrical member 56threaded in the larger diameter portion of the main piston. The piston53 includes a portion 57 fitting the cup 54 and provided with sealingrings 58 to prevent leakage, and a reduced portion 60 extending upwardlythrough the reduced diameter portion 55 of the chamber 52. The upperportion 60 of the piston 53 acts as a guide and a reduced portion 61provides communication between the larger diameter chamber or cup 54 anda plurality of downwardly inclined discharge passages 62.

When the operation of the hydraulic pump starts, high pressure liquid isadmitted to the chamber 34 and immdiately is applied to the lower sideof the piston 57 through a port 63, which passes through the weightingdisc 51 and the bottom of the main piston 48. This first application ofthe high pressure liquid forces the piston 53 suddenly upwardly anddischarges liquid through the ports 62; the resulting downwardlydirected jets of liquid create turbulence and agitate sediment lying onthe top of the main piston and facilitate the discharge of the sedimentwith the liquid forced through the check valves 41, thereby preventingexcessive accumulation of sediment and the trapping of sediment in thepump.

The control system illustrated in FIG. 2a is arranged to utilize thehigh pressure control of the hydraulic pump for initiating the returnstroke of the piston. In this figure, the structural parts aredesignated by the same numerals as in FIG. 2. A control valve 59 isprovided in the hydraulic fluid supply line 33 to deliver fluid from thepump 27 to the chamber 34 below the piston when the valve is in theposition indicated; when the valve is turned 90° counterclockwise, theline 33 is connected to a line 33' to connect the chamber 34 directly tothe reservoir for the return of fluid.

During the operation of the system of FIG. 2a, when the piston 48 hasbeen driven to its uppermost position, it strikes the stop 45' and theimmediate pressure surge actuates a pressure sensitive control 59' whichactuates relay 60' which energizes a solenoid 61' to move the valve byan arm 59' and shift the valve 59 to bypass the pump 27 and return fluidfrom the chamber 34 to the reservoir 30. At the same time, the relay 60'opens a switch 62' to de-energize the motor 28. The piston movesdownwardly by gravity to force liquid from the chamber 34 to thereservoir until the piston comes to rest on the spring-stop 35'. Themotor remains de-energized until the cylinder 14 has been filled withliquid to the level at which the float switch 38 operates. The motor 27is thus started and the cycle is repeated.

The embodiment of the invention illustrated in FIG. 3 provides anarrangement whereby the electrical connections to the motor and itscontrol are made through a detachable mandrel or plug which may belowered on a wire line into position on the pump assembly. As shown inthis figure, the plug or mandrel is indicated at 65. It is shaped as anelongated cartridge of cylindrical configuration with rounded ends. Theoutside wall of the mandrel is provided with a coating 66 of arelatively soft rubber or plastic which is bonded to the surface of themandrel shell. Three spring biased contacts 67, 68 and 69 are providedin the lower portion of the mandrel and are arranged so that when themandrel is in position in a socket or receiver assembly 71, they engagethree annular contact rings 72, 73 and 74, respectively. The mandrel isprovided with an attaching loop or ring 75 for securing a wire line 76and the cable conductor comprising three electrical leads indicated at77 provides three phase power and is secured to the wire line and entersthe top of the mandrel for connection with the contacts 67, 68 and 69.The mandrel is guided and positioned by an upper cone-shaped receiver 78mounted on the inner walls of a production tubing 80 and a lowerfunneled or flared entrance element 81 formed as a part of the receiverassembly 71.

When the mandrel 65 is lowered into the well through the productiontubing 80, it is first centered by an upper flared guide 82 and thenmoves downwardly through the flared entrance element 81 and into theplug socket of the receiver assembly 76. Because of its configurationand weight, the mandrel is seated within the socket in a position suchthat the contacts 67, 68 and 69 are in engagement with the contact rings72, 73 and 74, respectively. A supporting structure or spider 83 isprovided for supporting the socket assembly 71 and is provided withopenings 84 for affording a passage for liquid from the pump assemblybelow up into the production tubing 80.

The socket or receiver assembly 71 comprises a double walled cup-likestructure to which the bottom edge or face of the flared receiver 81 issecurely attached. The outer wall indicated at 86 is welded or otherwiserigidly secured to the supporting spider, and the spaced walls provideprotection for the electric leads which are connected to the electricmotor of the pumping unit through a fitting 87 mounted on the top of thehydraulic fluid reservoir indicated at 30a, the reservoir being closedby an end plate 88 and attached to the fitting 87 by means of anintermediate plate 90. Openings in the bottoms of both cup-like wallsprovide free passage for fluids when the mandrel is moved into orremoved from the socket assembly. The fluids from the pump flow upwardlythrough openings between hanger lugs 42a which are supported on lugs 43aas are the lugs 43 in FIG. 2.

The guide members 81 and 82 are also provided with perforations toafford upward passage of the produced liquid. This arrangement providesprotection for the electrical conductor 77 and provides for the readydisconnection of the electric current supply. The internal wall of thesocket of the assembly 71 is provided with a plurality of pairs of "o"rings 85 which engage the soft rubber wall of the mandrel, and providean effective seal between adjacent conductors when the mandrel is inposition.

In the modification illustrated in FIG. 4, an arrangement is providedwhereby the entire pump assembly may be installed in the well casing ona wire line. As shown in this figure, a pump assembly embodying theinvention, and indicated at 91, is mounted by means of lugs and supports42b and 42c within a cylindrical housing 92 and is lowered into the wellon a wire line 93. The wire line is secured to a spring biased plunger94, which is slidably mounted at the center of a wall or partition 95welded or otherwise secured to the inner seal of the housing 41. Aspring 96 urges the wall downwardly and is compressed by the weight ofthe pump assembly when the wire line is under tension. The electricsupply cable 20b which may be tied to the wire line passes through anopening in the plate 95 and thence to the pump assembly 91.

An expansible packer 97 is mounted about the housing 92 above thepartition 95 and is arranged to be inflated when the pump is in positionin the well. The inflation of the packer is controlled by a timer 98which is set to activate a valve 100 at a predetermined time after thepump has reached the position where it is to be installed and releasesgas under pressure from a tank 101 to the packing through an inlet pipe102; when inflated, the packer seals off the well casing below it. Avalve 103 is provided in order to open and close an exhaust pipe 104between the packer and the interior of the housing above the partition.This valve is actuated by movement of the plunger 94 with respect to thepartition 95; for this purpose the valve is provided with an actuatingarm 105 which lies in the path of an arm 106 on the plunger.

When the pump assembly is in position and the wire line is slacked off,the plunger 94 is in the position shown in FIG. 4 with the arms 105 and106 out of engagement and the valve 103 closed. When the wire line 93 ispulled upwardly, the plunger moves up until the spring 96 is fullycompressed - in this position the arm 106 has moved the arm 105 upwardlyto open the valve 52 and release the gas charge from the packer. Thepacker having been released, the pump assembly may now be pulled fromthe wall.

This packer construction enables the pump assembly to be installedeasily before actuating the packer and to be removed withoutinterference from the packer.

The pump assembly of this invention is easily installed in cased wells,operates only when there is sufficient liquid for pumping and thusprovides economy in installation and in operation.

Various other applications and modifications of this invention willoccur to those skilled in the art and while specific embodiments havebeen illustrated and described, it is not desired to limit the inventionthereto and it is intended, by the appended claims, to cover allmodifications within the spirit and scope of this invention.

I claim:
 1. In a deep well pump assembly of the type including anupwardly extending cylinder having therein a reciprocating piston forreceiving liquid from a reservoir formation and delivering liquid to thesurface and means for actuating the piston dependent upon theaccumulation of a predetermined quantity of liquid in said cylinderabove the piston, the improvement which comprises:means including ahydraulic pump mounted in said assembly and having its outlet connectedto deliver liquid to said cylinder below said piston for driving saidpiston upwardly in said cylinder to discharge fluid from said cylinder,said cylinder below said piston constituting an expansible chamber, saidmeans dependent upon the accumulation of a predetermined quantity ofliquid in said cylinder above said piston including a sensor in saidcylinder for detecting the level of liquid therein and connected toinitiate the operation of said hydraulic pump, and means actuated bysaid piston at the upper end of its stroke and controlling said pistondriving means for returning said piston to its bottom position in saidcylinder.
 2. The invention of claim 1 including an electric motor fordriving said hydraulic pump and wherein said means dependent upon apredetermined quantity of liquid in said cylinder includes a floatactuated switch for controlling said motor.
 3. The invention of claim 1wherein said means actuated by said piston includes a switch having anoperating member in the path of said piston.
 4. The invention of claim1, wherein said hydraulic pump includes an over-pressure release, andsaid assembly includes a rigid stop in the path of said piston forstopping said piston in the event of failure of said piston returncontrol, whereby said over-pressure release operates to preventexcessive high pressure of the hydraulic fluid.
 5. The invention ofclaim 1, including a hydraulic pump release switch at the bottom of saidexpansible chamber for stopping said hydraulic pump upon return of saidpiston to its bottom position.
 6. The invention of claim 1, wherein saidassembly includes a hydraulic fluid reservoir, and said means actuatedby said piston at the upper end of said stroke comprises a stop in saidcylinder in the path of said piston, pressure sensing means on theoutlet side of said hydraulic pump subject to the pressure of the fluidat the outlet of said hydraulic pump, and means utilizing said pressuresensing means and dependent upon a surge of pressure upon engagement ofsaid piston with said stop for providing open communication between saidexpansible chamber and said reservoir, whereby said piston returns bygravity to its lowermost position in said cylinder and the hydraulicfluid is returned to said reservoir.
 7. The invention of claim 6including an electric motor for driving said hydraulic pump and secondmeans dependent upon said surge of pressure for de-energizing saidmotor.
 8. In a deep well pump assembly of the type including an upwardlyextending cylinder having therein a reciprocating piston for receivingliquid from a reservoir formation and delivering liquid to the surfaceand means for actuating the piston dependent upon the accumulation of apredetermined quantity of liquid in said cylinder above the piston, theimprovement which comprises:means including a hydraulic pump mounted insaid assembly and having its outlet connected to deliver liquid to saidcylinder below said piston for driving said piston upwardly in saidcylinder to discharge fluid from said cylinder, said cylinder below saidpiston constituting an expansible chamber, said means dependent upon theaccumulation of a predetermined quantity of liquid in said cylinderabove said piston including a sensor in said cylinder for detecting thelevel of liquid therein and connected to initiate the operation of saidhydraulic pump, means actuated by said piston at the upper end of itsstroke and controlling said piston driving means for returning saidpiston to its bottom position in said cylinder, said piston including aninternal cylinder and means for admitting liquid thereto from above saidpiston and a second piston mounted for reciprocation in said internalcylinder and being biased to a bottom position, means for admittinghydraulic fluid under pressure to the underside of said second pistonfor forcing said second piston upwardly in said internal cylinder todischarge liquid therefrom, and means for directing the dischargedliquid downwardly toward the top of said first piston to agitate theliquid adjacent thereto.
 9. A deep well pump assembly, including anelongated cylindrical housing for insertion in a well casing adjacent aliquid producing formation, said housing having a partition thereindividing it into an upper chamber and a lower chamber,means fordelivering fluids from said housing to the surface, means for affordinga flow of fluid from said lower chamber to said upper chamber andincluding means for preventing a reverse flow of fluid, a piston mountedin said lower chamber for reciprocation therein, means closing thebottom end of said housing for providing a closed expansible chamberbelow said piston, a hydraulic pump mounted in said upper chamber, anelectric motor for driving said hydraulic pump, a hydraulic fluidreservoir mounted on said housing in said upper chamber, means forconnecting said hydraulic pump to receive fluid from said reservoir andto deliver fluid to said expansible chamber to drive said pistonupwardly in said lower chamber and to pump fluids through said upperchamber to the surface, means for admitting fluids from a reservoirformation to the upper portion of said lower chamber and for preventingreverse flow to the formation, means dependent upon the accumulation ofliquid in said lower chamber to a predetermined level for initiating theoperation of said hydraulic pump to drive said piston upwardly, meansdependent upon movement of said piston to a predetermined upper postionfor actuating said hydraulic pump to return fluid from said expansiblechamber to said reservoir and for returning said piston to its bottomposition, and means dependent upon movement of said piston to its bottomposition for stopping operation of said hydraulic pump.
 10. A deep wellpump assembly as set forth in claim 9, wherein said means for initiatingoperation of said hydraulic pump includes a float actuated switch atsaid predetermined liquid level in said lower chamber for energizingsaid electric motor to drive said hydraulic pump, and said means foractuating said hydraulic pump to return fluid to said reservoir includesa switch at the upper end of said lower chamber having an actuatingelement in the path of said piston for controlling said electric motorto initiate the return stroke of said piston.
 11. A deep well pumpassembly, including an elongated cylindrical housing for insertion in awell casing adjacent a liquid producing formation, said housing having apartition therein dividing it into an upper chamber and a lowerchamber,means for delivering fluids from said housing to the surface,means for affording a flow of fluid from said lower chamber to saidupper chamber and including means for preventing a reverse flow offluid, a piston mounted in said lower chamber for reciprocation therein,means closing the bottom end of said housing for providing a closedexpansible chamber below said piston, a hydraulic pump mounted in saidupper chamber, an electric motor for driving said hydraulic pump, ahydraulic fluid reservoir mounted on said housing in said upper chamber,means for connecting said hydraulic pump to receive fluid from saidreservoir and to deliver fluid to said expansible chamber to drive saidpiston upwardly in said lower chamber and to pump fluids through saidupper chamber to the surface, means for admitting fluids from areservoir formation to the upper portion of said lower chamber and forpreventing reverse flow to the formation, means dependent upon theaccumulation of liquid in said lower chamber to a predetermined levelfor initiating the operation of said hydraulic pump to drive said pistonupwardly, means dependent upon movement of said piston to apredetermined upper position for actuating said hydraulic pump to returnfluid from said expansible chamber to said reservoir and for returningsaid piston to its bottom position, means dependent upon movement ofsaid piston to its bottom position for stopping operation of saidhydraulic pump, means for suspending said assembly on a wire line forinsertion in a well casing, an inflatable packer attached about saidhousing above said means for admitting fluid to said lower chamber, andmeans within said upper chamber for inflating said packer after releaseof tension on the wire line for providing a seal between said housingand the well casing, said inflating means including a cylinder of gasunder pressure and means for releasing the gas to inflate the packer ata predetermined time after insertion of the pump assembly in a well, andvalve means dependent upon the tensioning of the wire line for releasingthe gas from said packer.
 12. A deep well assembly including anelongated cylindrical housing for insertion in a well casing adjacent aliquid producing formation, said housing having a partition thereindividing it into an upper chamber and a lower chamber,means fordelivering fluids from said housing to the surface, means for affordinga flow of fluid from said lower chamber to said upper chamber andincluding means for preventing a reverse flow of fluid, a piston mountedin said lower chamber for reciprocation therein, means closing thebottom end of said housing for providing a closed expansible chamberbelow said piston, a hydraulic pump mounted in said upper chamber, anelectric motor for driving said hydraulic pump, a hydraulic fluidreservoir mounted on said housing in said upper chamber, means forconnecting said hydraulic pump to receive fluid from said reservoir andto deliver fluid to said expansible chamber to drive said pistonupwardly in said lower chamber and to pump fluids through said upperchamber to the surface, means for admitting fluids from a reservoirformation to the upper portion of said lower chamber and for preventingreverse flow to the formation, means dependent upon the accumulation ofliquid in said lower chamber to a predetermined level for initiating theoperation of said hydraulic pump to drive said piston upwardly, meansdependent upon movement of said piston to a predetermined upper positionfor actuating said hydraulic pump to return fluid from said expansiblechamber to said reservoir and for returning said piston to its bottomposition, means dependent upon movement of said piston to its bottomposition for stopping operation of said hydraulic pump, said means fordelivering fluids including means for connecting said housing to a fluidproduction line, an electric cable for supplying current to saidelectric motor, an electric connection and guide socket mounted at thetop of said assembly guide above and spaced from said guide socket andan elongated mandrel constructed to be lowered on a wire line and to bedirected into said socket, and complementary electric contact members insaid guide socket and on said mandrel for completing electricalconnections to said motor, said mandrel having an electric cableconnected to its contacts and arranged to extend along the wire line.13. In a deep well pump assembly of the type including an upwardlyextending cylinder having therein a free reciprocatable piston forreceiving liquid from a reservoir formation and delivering liquid to thesurface and means for actuating the piston dependent upon theaccumulation of a predetermined quantity of formation liquid in thecylinder above the piston, the improvement which comprises:meansincluding a hydraulic pump mounted in said assembly and having itsoutlet connected to deliver liquid to said cylinder below said pistonfor driving said piston upwardly in said cylinder to discharge fluidfrom said cylinder, said cylinder below said piston constituting anexpansible chamber, means including a liquid level sensor in saidassembly adjacent the top of said cylinder and responsive to a liquidlevel dependent upon a predetermined filling of said cylinder forstarting said pump, and means in the upper end of said cylinder andactuated by said piston at the upper end of its stroke and controllingsaid piston driving means for returning said piston to its bottomposition in said cylinder.
 14. A deep well pump assembly as set forth inclaim 13, including means for suspending said assembly on a wire linefor insertion in a well and operation therein.
 15. A deep well pumpassembly as set forth in claim 13, including an electric motor in saidassembly for driving said pump, a stop for limiting the upward movementof said piston, and means dependent upon a surge of pressure uponengagement of said piston with said stop for deenergizing said motor.16. In a deep well pump assembly of the type including an upwardlyextending cylinder having inlet and outlet valves in the upper portionthereof and a piston reciprocable therein and biased by gravity towardits lowermost position, the assembly being positionable in a well borefor receiving liquid from a reservoir formation and for delivering theliquid to the surface and means for actuating the piston dependent uponthe accumulation of a predetermined amount of reservoir liquid in thecylinder above the piston, the method of operation which comprises:a.providing within the assembly a source of liquid under pressure; b.allowing liquid from the formation to enter the cylinder until aquantity of reservoir liquid has accumulated in the cylinder above thepiston to a predetermined level; c. upon attainment of saidpredetermined level supplying liquid under pressure from the source tothe cylinder below the piston to drive the piston upwardly and dischargethe accumulated liquid from the cylinder; d. after discharge of theaccumulated liquid stopping the supply of liquid under pressure forreleasing the pressure below the piston and allowing the piston toreturn to its lowermost position and returning the liquid from below thepiston to the source; and e. repeating the steps of accumulatingformation liquid to the predetermined level, driving the piston upwardlyand discharging the accumulated reservoir liquid from above the piston,and returning the piston to provide continued production of thereservoir liquid.